Straight through LAN cable should be used when the two cascading
ports of fiber optical switch ( fiber media converter) are ordinary
MDI-X port and MDI-II port. Cross LAN cables should be used when
two cascading ports are common MDI-X ports or MDI-II ports.

Whether 10Base-T Ethernet, 100Base-TX Fast Ethernet or 1000Base-T
Gigabit Ethernet, the length of LAN cable used in cascaded fiber
switches ( fiber media converter) can reach 100 meters, which is
exactly the same length from switches to computers. As a result, in
addition to the number of ports that can be extended, the other use
of cascade fiber media converter is to quickly extend the network
diameter. When 4 switches are cascaded, the network span can reach
500 meters. This distance is enough for a small network in the same
building.

Now more and more fiber switches (fiber media converter) provide
Uplink ports, making connections between switches simpler. The
Uplink port is dedicated to connect with other switches. It can
connect the uplink port to any other port of other optical switch (
fiber media converter except Uplink port by using straight through
patch cord. This connection is exactly the same as the connection
between a computer and a switch. It should be noted that some brand
switches (such as 3Com) use a common port as Uplink port, and use a
switch (MDI/MDI-X switch) to switch between two types and use
Uplink port and straight cable to cascade switch.

If the fiber switch (fiber media converter) does not provide a
specialized cascade port (Uplink port), then the crossover patch
cord should be used to connect the two ordinary ports of two
switches (fiber media converters) to expand the number of network
ports. It is important to note that when using a common port to
connect to a switch, a cross line must be used instead of a
straight line. The cross line is cascaded through a common port.